<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
</head>
<body>
<div id="A" style="position:relative; background:red;">
	<span style="width:100px;height:100px;float:left;">content</span>
</div>

<script language="javascript">
	alert(document.getElementById("A").scrollHeight);
</script>

</body>
</html>